Color Image Compression and Encryption Algorithm Based on 2D Compressed Sensing and Hyperchaotic System

With the advent of the information security era,it is necessary to guarantee the privacy,accuracy,and dependable transfer of pictures.This study presents a new approach to the encryption and compression of color images.It is predicated on 2D compressed sensing(CS)and the hyperchaotic system.First,an optimized Arnold scrambling algorithm is applied to the initial color images to ensure strong security.Then,the processed images are con-currently encrypted and compressed using 2D CS.Among them,chaotic sequences replace traditional random measurement matrices to increase the system’s security.Third,the processed images are re-encrypted using a combination of permutation and diffusion algorithms.In addition,the 2D projected gradient with an embedding decryption(2DPG-ED)algorithm is used to reconstruct images.Compared with the traditional reconstruction algorithm,the 2DPG-ED algorithm can improve security and reduce computational complexity.Furthermore,it has better robustness.The experimental outcome and the performance analysis indicate that this algorithm can withstand malicious attacks and prove the method is effective.

In situ localization of BiVO_(4) onto two-dimensional MXene promoting photoelectrochemical nitrogen reduction to ammonia

The existing industrial ammonia synthesis usually adopts the Haber-Bosch process,which requires harsh conditions of high temperature and high pressure,and consumes high energy.Under this circumstance,photoelectrochemical(PEC)catalysis is regarded as a promising method for N_(2) reduction reaction(NRR),but bears problems of low efficiency and yield.Thus,exploring active catalysts remains highly desirable.In this work,BiVO_(4)@MXene hybrids have been facilely synthesized by a hydrothermal route.The heterojunctions by the in situ growth of BiVO_(4) onto two-dimensional(2D)MXene greatly increase the NRR efficiency:under photoelectric conditions,the optimized NH_(3) yield is 27.25µg h^(-1) cm^(-2),and the Faraday efficiency achieves 17.54% at−0.8 V relative to the reversible hydrogen electrode(RHE),which are higher than most state-of-the-art NRR(photo)electrocatalysts.The mechanism speculation shows the enhanced light absorption range and the heterojunction formation largely promote the separation and the transfer efficiency of photogenerated carriers,thereby improving the PEC catalytic ability.Therefore,this work provides a hybrid route to combine the advantages of photo and electric catalysis for effective artificial nitrogen fixation.

ORP8 acts as a lipophagy receptor to mediate lipid droplet turnover

Lipophagy,the selective engulfment of lipid droplets(LDs)by autophagosomes for lysosomal degradation,is critical to lipid and energy homeostasis.Here we show that the lipid transfer protein ORP8 is located on LDs and mediates the encapsulation of LDs by autophagosomal membranes.This function of oRP8 is independent of its lipid transporter activity and is achieved through direct interaction with phagophore-anchored LC3/GABARAPs.Upon lipophagy induction,ORP8 has increased localization on LDs and is phosphorylated by AMPK,thereby enhancing its affinity for LC3/GABARAPs.Deletion of ORP8 or interruption of ORP8-LC3/GABARAP interaction results in accumulation of LDs and increased intracellular triglyceride.Overexpression of ORP8 alleviates LD and triglyceride deposition in the liver of ob/ob mice,and Osbpl8 mice exhibit liver lipid clearance defects.Our results suggest that ORP8 is a lipophagy receptor that plays a key role in cellular lipid metabolism.

Passivity-based decentralized stabilization of multi-agent systems with uncertainty and mixed delays

In this paper, we investigate a decentralized stabilization problem of uncertain multi-agent systems with mixed delays including discrete and distributed time-varying delays based on passivity stability. We design a decentralized state-feedback stabilization scheme such that the family of closed-loop feedback subsystems enjoys the delay-dependent passivity stability for each subsystem. Then, by employing a new Lyapunov-Krasovskii function, a linear matrix inequality （LMI） approach is developed to establish the delay-dependent criteria for the passivity stability of multi-agent systems. The sufficient condition is given for checking the passivity stability. The proposed LMI result is computationally efficient. An example is given to show the effectiveness of the method.

A quadruple helicene with a rubicene core: synthesis, structural analyses and properties

We report the synthesis of a quadruple helicene with a rubicene core R1 by a Scholl reaction.Among the 10 stereoisomers including 4 pairs of enantiomers and 2 meso isomers,only 2 pairs of enantiomers and 1 meso isomer have been isolated.The sample structures were unambiguously determined by X-ray crystallography to be(P,P)_(6)-(P,P)_(5)/(M,M)_(6)-(M,M)_(5)-R1-A,which has a propeller-shaped structure,and(M,M)_(6)-(P,P)_(5)/(P,P)_(6)-(M,M)_(5)-R1-B and(M,P)_(6)-(P,M)_(5)-R1-C,which have saddle-shaped structures.The chiral resolutions of R1 were carried out by chiral HPLC,revealing two pairs of chiral stereoisomers(P,P)_(6)-(P,P)_(5)/(P,P)_(6)-(M,M)_(5),(M,M)_(6)-(P,P)_(5)/(M,M)_(6)-(M,M)_(5) as well as a meso isomer(M,P)_(6)-(P,M)_(5),which were further characterized by CD spectroscopy and time-dependent density functional theory(TD-DFT)calculations.Surprisingly,the UV-vis absorption and emission spectra of these resolved stereoisomers and unresolved R1 were almost identical.In addition,the chemical oxidation of R1 led to the formation of radical cations and dications at room temperature.

Enhance the performance of polymer solar cells via extension of the flanking end groups of fused ring acceptors

Two new fused ring electron acceptors(FREAs)IDT-IC-T and IDT-IC-B with thienyl or phenyl substituents at the terminal INCN unit are synthesized.Theoretical calculations indicate that the two acceptors dominantly favor an intermolecularπ-πstacking between the flanking terminal groups.The twist angle between the aryl substituent and INCN unit has a significant influence on theπ-πstacking distance of terminal unit.IDT-IC-T with a smaller twist angle has a shorterπ-πstacking distance than that of IDT-IC-B with a larger twist angle.In addition,extending the conjugation also affects the blend film morphology.IDT-IC-T and IDT-IC-B based photoactive films show appropriate nanoscale phase separations;whereas,blend films based on the parent compound IDT-IC show large-size acceptor domains.As expected,PBDB-T:IDT-IC-T blend films show higher and more balanced electron and hole mobilities.Moreover,these two acceptors present a good charge-transport connectivity arising from the extended conjugation and the increased intermolecular overlapping.Ultimately,IDT-IC-T demonstrates the highest electron mobility(1.47×10^(-4)cm^2V^(-1)s^(-1))and the best power conversion efficiency(PCE)of 9.43%.As for IDT-IC,which only shows an electron mobility of 7.33×10^(-5)cm^2V^(-1)s^(-1)and a PCE of 5.82%.These findings provide a facile and effective way to improve the photovoltaic performance.